The present invention relates to a closed motor-driven compressor for use in refrigerators, air conditioners or the like.
Recently, closed motor-driven compressors are demanded to have a high energy efficiency, and it is well known that a suction muffler having a low thermal conductivity and made of, for example, synthetic resin is suited for use in such compressors.
Japanese Laid-Open Patent Publication (unexamined) No. 10-47248 discloses a closed motor-driven compressor as shown in FIGS. 11 and 12. This compressor includes a compression component 2 and an electric component 3, both elastically supported within a closed vessel 1. The compression component 2 includes a cylinder 4, a piston 5 reciprocatingly accommodated in the cylinder 4, a valve plate 6 mounted on the cylinder 4 so as to cover an opening defined therein, and a cylinder head 7 secured to the cylinder 4. A suction muffler 8xe2x80x2 made of synthetic resin and made up of three elements is mounted on the cylinder head 7 for introducing a refrigerant gas into the cylinder 4. The suction muffler 8xe2x80x2 is connected to a suction pipe 9 extending through a side wall of the closed vessel 1 to introduce the refrigerant gas into the closed vessel 1.
As shown in FIG. 13, the muffler 8xe2x80x2 includes a first element 29, a second element 30 to which the first element 29 is secured, and a third element 31 secured to the second element 30. As shown in FIG. 14, the first element 29 has an inwardly protruding guide rib 32 integrally formed therewith. The guide rib 32 acts to facilitate the assembling of the first and second elements 29, 30. After the first and second elements 29, 30 have been assembled using the guide rib 32, they are assembled with the third element 31, and all of them are joined together by ultrasonic welding.
In the closed motor-driven compressor of the above-described construction, the refrigerant gas from the low-pressure side in a refrigerating cycle is introduced into the closed vessel 1 through the suction pipe 9 and then into the cylinder 4 through the suction muffler 8xe2x80x2 before the refrigerant gas is compressed by the piston 5.
In the above-described construction, however, because the suction muffler 8xe2x80x2 is made of synthetic resin, it is apt to be deformed after injection molding. Accordingly, a difficulty is encountered in assembling the first and second elements 29, 30 with the use of the guide rib 32.
U.S. Pat. No. 5,341,654 discloses a refrigeration compressor, wherein V-shaped ribs extend laterally across respective flange portions as well as a tubular member adjacent the opposite ends of the flange portions of a muffler, which is fabricated from a polymeric composition.
The present invention has been developed to overcome the above-described disadvantages.
It is accordingly an objective of the present invention to provide a closed motor-driven compressor having an improved suction muffler that facilitates the assembly of its elements.
In accomplishing the above and other objectives, the closed motor-driven compressor according to the present invention includes a closed vessel, a compression component elastically supported within the closed vessel, an electric component elastically supported within the closed vessel for driving the compression component, and a suction muffler mounted on the compression component and including a plurality of elements assembled together and each made of synthetic resin. One (first element) of the plurality of elements has a guide rib integrally formed therewith that is tapered down toward an adjoining one (second element) of the plurality of elements. The tapered guide rib acts to reform deformation of the second element into which it is inserted, thus facilitating an assembly of the first and second elements.
The guide rib is formed discontinuously or intermittently along a peripheral edge of the first element. By so doing, strains caused by the cooling of the first element after injection molding are relatively small, thus reducing deformation of the first element.
The first element may have first and second peripheral portions and third and fourth peripheral portions each interposed between the first and second peripheral portions, wherein the first and second peripheral portions have first and second radii of curvature, respectively, while the third and fourth peripheral portions have third and fourth radii of curvature, respectively, that are smaller than the first and second radii of curvature, and wherein the guide rib is formed at the third or fourth peripheral portion and at the first and second peripheral portions adjacent thereto.
In assembling the first and second elements, the first and second portions of the second element having large radii of curvature are subjected to relatively small deformation, while the third and fourth portions of the second element having small radii of curvature are subjected to larger deformation. Accordingly, the guide rib formed at the first and second peripheral portions of the first element can be readily inserted into the corresponding portions of the second element, and the guide rib gradually reforms the deformation of the second element. Such insertion facilitates subsequent insertion of the guide rib into the third and fourth portions of the second element, making it possible to realize automated assembling of suction mufflers.
The plurality of elements are secured to one another by welding. The welding reduces a leakage of suction gas from the suction muffler.
Alternatively, the plurality of elements are secured to one another by fastening means such, for example, as rivets, screws, or the like. The use of such fastening means requires no expensive welding machine or the like.
Again alternatively, the plurality of elements are secured to one another by introducing projections formed therewith into openings defined therein. The assembling of the elements by engagement of the projections with the openings requires no fastening means referred to above.